At the point where you loop through each ball and call the draw(), update(), and collisionDetect() functions for each ball, make these functions only call if the ball currently exists.
please help, i really don’t really understand with this one can someone help explain it, instead of opening my mind or how should i think to solve this.
Every ball should have a property exists. If you set it to true at the beginning and change it to false when the ball is catched by the evil circle, you can check for this variable at the appropriate places in your code.